Vehicle tire



Patented Aug. 12, 1924.

4"UNITED STATES PATENT OFFICE.

v:PAUL W. LITOHFIELD, or mon, oHIo, AssrGNom'Tc THE GOODYEAR TIRE aRUBBER COMPANY, ormoni, omo, A CORPORATION or omo.

VEHIcLE Tran.

Application led'August v27 1921. Serial 170.495,86.

To all whom; it may concern.'

Be it known that I, PAUL W. LITCHFIELD, a citizen vof the United States,residin at Akron, in the county of Summit and tate of Ohio, haveinventedl new and useful Improvements `in.`Ve hicle Tires, of which thefollowing is a specification.

vMy invention relates to cushion tires and itis particularly directed tothe rovision of a tread surface that shall have improved operatingcharacteristics.

In cushion tires that have heretofore been devised, it has beencustomary to so form the non-skid tread figures that they apparentlystand out from the body of the tire and are of substantially the sameheight over the tread surface.

My improved tire' has the tread figures delineated by a series ofindentures in the tread face. The tread figures therefore have theappearance of being formed as a part of the body of the tire instead ofbeing raised above the tire body. These elements substantially on theline 33, of the tire'` shown in Figure 1;

Figure 4 is asectional view taken -through the longitudinal center ofone of the indentures, and is indicated as being taken on line 4-4 ofFigure l;

Figure 5 is a plan view of the tread surface of a tire embodying amodified construction and incorporating the essential features of myinvention,l

Fi l re 6 is a side view of a portion of the tire s own in Fi 5;

Figure 7 is a ragmentary sectional view taken on the line 7-7 of Fig. 5;

Figure 8 is a transverse sectional view taken substantially on lthe line8-8 of the tire shown in Fig. 5;

Figure 9 is a corresponding sectional view taken on the line 9 9 of thetire shown in Fig. 5; and

Fig. 10 is a sectional view through one of the indentures taken on theline 10-10 of Fig. 5.

In the discussion of my improved form of tire, have chosen tread figuresofy diamond form as clearly illustrating the principles of my invention.This is, however, not to be construed as alimitationof my invention,since any tread figure embodying like characteristicscould be employed.l

Attention is first invitedI to the tire shown in Figures l to 4,inclusive, of the accompanying drawings, which'has a series ofindentures l() traversing the tread surface. These'indentures delineatetread portions 11 of substantially diamond shape and portions 12 thatextend from the side of the tire to the tread face to complete thedesign of the surface. The` indentures, that have been shown asillustrative of the principles of my invention, extend diagonallyvrelative to theedge of the tire.

@ne of the features of major importance with relation to the treadIindentures, is the fact that the depth of each of the indenturesincreases directly in accordance with ,its distance from the 'side ofthe tire. The effect ofthis variation in the depth of the indentures isto form separated tread p0rtions that-are of greater de th along themedian line of the tire than a ong its edges.

This vparticular feature is most clearly indicated in Figures 2, 3 and4. rlhe diagonal sectional View of the tire shown in Fig. 4, whichrepresents the section formed by a plane passing through the bottomv ofone of theV indentures or grooves in the tread of the tire, indicates,in a general way, the manner in which the depth of the groove orindenture increases as 1t progresses toward the middle of the tire, anddecreases as it a proaches elther of the In t 1s showing, the surfacecurvature of thegtire has been-neglected for the sake of clearness ofillustration. The tire is shown as though its treadsm# `face were aplane surface such as would be Since all of t e grooves or indentures 10I are of the same general form, the circumferential projection of thebottoms of the any point on the tread surface b the distance below thetread surface of t e line 14. rllhis line, therefore, constitutes alocus of the circumferential pro'ections of the `bottom lines ofthesevera grooves or indentures.

Itis also important to maintain the width of the indenture somewhat lesslthan the width of the tread figures. This is obtained vao by' spacingthe indentures in each series a greater distance than thewidth thereof.

Since the upstanding tread figures are of much reater depth in the zoneof the 4 medianfp ane of the tire than along the -in order that thebuttons or tread edges of the tread surface, some provision is obviouslydesirable to stiifen the centrally located ii res without materiallyaltering their resllient characteristics. For this pur ose a series ofreinforcing elements `16 are ormed between adjacent tread portions insuch manner as to support such portions against abnormal lateralVdisplacement. These' reinforcing lelements are positioned within theindentures, preferably at their intersections, and are preferablydisposed a uniform distance below the tread surface. The sectional viewsshown in Figures 2,. 3

land 4 indicate the relative position of the several reinforcingelements.

The improved operating characteristics of my tire. will be appreciatedif attention is directed to the increased resilient features that areinherent when tread portions of greater de th are formed along themedian ortion o .the tread than have heretofore een rovided in tires ofthis type.

It as heretofore been cutomary to form tread portions 4of substantiallyuniform depth onfthe tire body. This resulted in an inner tread surfacethat was less yielding than the outer tread surface of the tire byreason of the greater confinement a ainst expansion of the several innertrea portions. It was necessary in such instances to provide relativelyshallow tread, figures rtions delineated by the indentures woul not bedestroyed or mutilated by the lateral thrust on the tread Surface. Avery definite limitation was, therefore, imposed on the depth of thetread portion that might be em loyed with fiat faced tires having treadres separated by the indentures or where the gures were formed above thetread body.

The use of indentures having va depth, particularly in con'unction withthe relnforcing strips form between tread portions, renders it ossible`to construct tread portions of muc greater depth than has .heretoforebeen customary.

The lateral shear that is imposed at the edges of the tire tread iseffectively restricted by the comparatively shallow tread portion formedat that point, whereas near the center of the tire where the shearforces are minimized, the tread portions have much greater depth and,therefore, greater yieldability in takin up these thrusts, and' alsoembody the ad itional advantages of .cushioning blows imposed at thecenter of the tire much more effectively than has heretofore beenpossible with wide faced cushion tires.

Figures 5 to 9, inclusive, illustrate a modiication of my invention in`which only a single series of separated tread portions 20 are formed onthe tread surface of the tire by the intefrsecting indentures 2 1.Reinforcing elements 22, y that are similar in .character and form tothe corresponding element 16 shown in the previousl described tire, areformed between adjacent tread portions of the tire. The edge 0rtions 23of the tread surface form an e ective protection for the points 20 ofthe treadigures. Thel varying depth of the several indentures iseffectively shown in Fig. 10, which is a sectional view on a planeextending along the line 10-10 of ig. 5. This illustratesvery clearlythe increased depth of indenture near the median line of the tire. It isbelieved that, in View of the precedin discussion of the operation ofthe tire s own in Fi res 1 to 4, additional discussion of the fgegturesof the tire shown in Figs. 5 to 10, inclusive, is unnecessary.

Although I have illustrated and described only two forms of myinvention, it.will be apparent that the principles thereof can beemployed to construct many other forms of resilient tires and embodyingdifferent tread. designs. I desire, therefore, that only suchlimitations shall be imposed on the spirit and scope of my invention asare indicated in the accompanying claims.

Y What I claim is:

1. A resilient tire having relatively narrow indentures of uniformlyvarying depths in the tread surface 'said mdentures being of greatestdepth a ong the median plane of the tread and being s aced a greaterdistance than the width o the indentures.

2. A resilient tire ha a substantially at tread surface and relativelynarrow tread indentures in said surface of uniformly varying depths, thedepth of the indentures being greatest at the center of the y, treadsurface, and said indentures be' s aced a greater distance than the widt ereof.

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of varying depths such that a surface passed through the bottoms of saidindentures would be outwardly concave on 'any transverse section.

4. A resilient tire having a series of intersecting tread indenturesof-varying depths, each of said tread indentures beiiig of such depththat the locus of the circumferential of the tire and the distancebetween adjas' cent indentures being greater than the Width of theindenture.

6. A resilient tire having relatively narrow intersecting treadindentures 'of varying depths, and a substantially flat tread surface,the depth of said indentures at an point -varying directly in accordanceWit their distance from the side of the tire.

7.. A resilient tireliaving indentures delineating a series of treadortions, and reinforcing strips extending tween adjacent tread portions,said reinforcing strips being of less height than the depth of saidindentures.

8. A resilient tire having a series of indentures formed in the Itreadsurface, and reinforcing elements formed between adjaf cent treadportions delineated by said 1ndentures, said reinforcing elements beinformed a uniform distance radially inward from the tread surface.

9. A resilient tire having a series of intersecting indentures in thetread surface, and rein-forcing elements connecting adjacent treadportions delineated by intersecting indentures.

10. A resilient tire having a series of intersecting indentures ofvarying depths in the tread surface thereof, the depths of saidindentures varying in accordance with the lateral distance from the sideof the tire, and reinforcing elements connecting adjaing indentures.A

cent tread portions delineated by intersect- 11. A resilient tirehaving-a series of intersecting indentures of varying depths in thetread surface thereof, the depths of said indentures varying inaccordance with the lateral distancev from the side of the tire, andreinforcin elements connecting adjacentl tread portions delineated byintersecting indentures, said rein forcing elements being disposedradially inward from the tread surface.

12. A resilient tire having tread portions delineated by indentures ofvaryin depths, and reinforcing elements dispose within said indenturesfor reinforcing said tread portions.

13. A resilient tire having tread portions delineated by indentures ofdepths varying in accordance with their distance from the lateral faceof the tire, and reinforcing elements formed within the dee est portionsof the indentures connecting a jacent tread portions. Y

14. A resilient tirehavin tread indentures of uniformly varying epths,said indentures being formed obli uely relative to the transverse andmedian p anes of the tire.

15. A resilient tire having indentures'in the tread surface of uniformlyva ing depths, said indentures being adapte to separate tread portionsinto complete unitary ii ures.

16. resilient tire having a lurality of se arated tread portions ada tevto form a suistantially dat tread sur ace, the tread portions disposedalong the median line of the tire losing of greater depth than the othertread portions.

In witness whereof l have hereunto si ned my naine in the presence oftwo subscr'i ing witnesses.

PAUL W. LlTCHFlELD. Witnesses:

E. J. Timms, WM. C. Motley.

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